Question

A particle is in SHM. When displacement is ‘a‘ potential energy is 8J. When displacement is ‘a‘ potential energy is 18J. What will be the potential energy when displacement is ‘a+b’?

(a) 50J

(b) 26J

(c) 10J

(d) 30J

Answer 1

Correct answer is (a) 50J

To explain I would say: 1/2ka^2 = 8 & 1/2kb^2 = 18.

We have to find value of 1/2k(a + b) ^2.      

∴ 1/2k(a + b)^2 = 8 + 18 + kab  

= 26+(k*4*6/k)    

= 26 + 24 = 50J.